<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Redis Caching Class
 *
 * @package       CodeIgniter
 * @subpackage Libraries
 * @category   Core
 * @author       Anton Lindqvist <anton@qvister.se>
 * @link
 */
class CI_Cache_redis extends CI_Driver
{
    /**
     * Default config
     *
     * @static
     * @var    array
     */
    protected static $_default_config = array(
        'socket_type' => 'tcp',
        'host' => '127.0.0.1',
        'password' => NULL,
        'port' => 6379,
        'timeout' => 0
    );

    /**
     * Redis connection
     *
     * @var    Redis
     */
    protected $_redis;

    /**
     * An internal cache for storing keys of serialized values.
     *
     * @var    array
     */
    protected $_serialized = array();

    // ------------------------------------------------------------------------

    /**
     * Class constructor
     *
     * Setup Redis
     *
     * Loads Redis config file if present. Will halt execution
     * if a Redis connection can't be established.
     *
     * @return    void
     * @see        Redis::connect()
     */
    public function __construct()
    {
        if (!$this->is_supported()) {
            log_message('error', 'Cache: Failed to create Redis object; extension not loaded?');
            return;
        }

        $CI =& get_instance();

        if ($CI->config->load('redis', TRUE, TRUE)) {
            $config = array_merge(self::$_default_config, $CI->config->item('redis'));
        } else {
            $config = self::$_default_config;
        }

        $this->_redis = new Redis();

        try {
            if ($config['socket_type'] === 'unix') {
                $success = $this->_redis->connect($config['socket']);
            } else // tcp socket
            {
                $success = $this->_redis->connect($config['host'], $config['port'], $config['timeout']);
            }

            if (!$success) {
                log_message('error', 'Cache: Redis connection failed. Check your configuration.');
            }

            if (isset($config['password']) && !$this->_redis->auth($config['password'])) {
                log_message('error', 'Cache: Redis authentication failed.');
            }
        } catch (RedisException $e) {
            log_message('error', 'Cache: Redis connection refused (' . $e->getMessage() . ')');
        }

        // Initialize the index of serialized values.
        $serialized = $this->_redis->sMembers('_ci_redis_serialized');
        empty($serialized) OR $this->_serialized = array_flip($serialized);
    }

    // ------------------------------------------------------------------------

    /**
     * Get cache
     *
     * @param    string $key Cache ID
     * @return    mixed
     */
    public function get($key)
    {
        $value = $this->_redis->get($key);

        if ($value !== FALSE && isset($this->_serialized[$key])) {
            return unserialize($value);
        }

        return $value;
    }

    // ------------------------------------------------------------------------

    /**
     * Save cache
     *
     * @param    string $id Cache ID
     * @param    mixed $data Data to save
     * @param    int $ttl Time to live in seconds
     * @param    bool $raw Whether to store the raw value (unused)
     * @return    bool    TRUE on success, FALSE on failure
     */
    public function save($id, $data, $ttl = 60, $raw = FALSE)
    {
        if (is_array($data) OR is_object($data)) {
            if (!$this->_redis->sIsMember('_ci_redis_serialized', $id) && !$this->_redis->sAdd('_ci_redis_serialized', $id)) {
                return FALSE;
            }

            isset($this->_serialized[$id]) OR $this->_serialized[$id] = TRUE;
            $data = serialize($data);
        } elseif (isset($this->_serialized[$id])) {
            $this->_serialized[$id] = NULL;
            $this->_redis->sRemove('_ci_redis_serialized', $id);
        }

        return $this->_redis->set($id, $data, $ttl);
    }

    // ------------------------------------------------------------------------

    /**
     * Delete from cache
     *
     * @param    string $key Cache key
     * @return    bool
     */
    public function delete($key)
    {
        if ($this->_redis->delete($key) !== 1) {
            return FALSE;
        }

        if (isset($this->_serialized[$key])) {
            $this->_serialized[$key] = NULL;
            $this->_redis->sRemove('_ci_redis_serialized', $key);
        }

        return TRUE;
    }

    // ------------------------------------------------------------------------

    /**
     * Increment a raw value
     *
     * @param    string $id Cache ID
     * @param    int $offset Step/value to add
     * @return    mixed    New value on success or FALSE on failure
     */
    public function increment($id, $offset = 1)
    {
        return $this->_redis->incr($id, $offset);
    }

    // ------------------------------------------------------------------------

    /**
     * Decrement a raw value
     *
     * @param    string $id Cache ID
     * @param    int $offset Step/value to reduce by
     * @return    mixed    New value on success or FALSE on failure
     */
    public function decrement($id, $offset = 1)
    {
        return $this->_redis->decr($id, $offset);
    }

    // ------------------------------------------------------------------------

    /**
     * Clean cache
     *
     * @return    bool
     * @see        Redis::flushDB()
     */
    public function clean()
    {
        return $this->_redis->flushDB();
    }

    // ------------------------------------------------------------------------

    /**
     * Get cache driver info
     *
     * @param    string $type Not supported in Redis.
     *                Only included in order to offer a
     *                consistent cache API.
     * @return    array
     * @see        Redis::info()
     */
    public function cache_info($type = NULL)
    {
        return $this->_redis->info();
    }

    // ------------------------------------------------------------------------

    /**
     * Get cache metadata
     *
     * @param    string $key Cache key
     * @return    array
     */
    public function get_metadata($key)
    {
        $value = $this->get($key);

        if ($value !== FALSE) {
            return array(
                'expire' => time() + $this->_redis->ttl($key),
                'data' => $value
            );
        }

        return FALSE;
    }

    // ------------------------------------------------------------------------

    /**
     * Check if Redis driver is supported
     *
     * @return    bool
     */
    public function is_supported()
    {
        return extension_loaded('redis');
    }

    // ------------------------------------------------------------------------

    /**
     * Class destructor
     *
     * Closes the connection to Redis if present.
     *
     * @return    void
     */
    public function __destruct()
    {
        if ($this->_redis) {
            $this->_redis->close();
        }
    }
}
